Is a Third Person Camera that allows to brings to the Main Camera of an scene in Unity3D to follow the main character that have a lookAt object in it's hierarchy

TP_Camera

using UnityEngine;
using System.Collections;

public class TP_Camera : MonoBehaviour 
{
	public static TP_Camera Instance;

	public Transform TargetLookAt;
	public float Distance = 5f;
	public float DistanceMin = 3f;
	public float DistanceMax = 10f;
	public float DistanceSmooth = 0.05f;
	public float X_MouseSensitivity = 5f;
	public float Y_MouseSensitivity = 5f;
	public float MouseWheelSensitivity = 5f;
	public float X_Smooth = 0.05f;
	public float Y_Smooth = 0.1f;
	public float Y_MinLimit = -40f;
	public float Y_MaxLimit = 80f;

	private float mouseX = 0;
	private float mouseY = 0;
	private float velX = 0;
	private float velY = 0;
	private float velZ = 0;
	private float velDistance = 0;
	private float startDistance = 0;
	private Vector3 position = Vector3.zero;
	private Vector3 desiredPositon = Vector3.zero;
	private float desiredDistance = 0;

	void Awake()
	{
		Instance = this;
		Debug.Log ("Awake of TP_Camera");
	}//Awake()

	// Use this for initialization
	void Start() 
	{
		Distance = Mathf.Clamp (Distance, DistanceMin, DistanceMax);
		startDistance = Distance;
		Reset ();
	}//Start()
	
	// Update is called once per frame
	void LateUpdate() 
	{
		if (TargetLookAt == null) {
			return;
		}

		HandlePlayerInput ();

		CalculateDesiredPosition ();

		UpdatePosition ();
	}//Update()

	void HandlePlayerInput()
	{
		var deadZone = 0.01f;

		// The right mouse button is down
		if (Input.GetMouseButton (1)) {
			mouseX += Input.GetAxis("Mouse X") * X_MouseSensitivity;
			mouseY += Input.GetAxis("Mouse Y") * Y_MouseSensitivity;
		}

		// clamp the mouse rotation in Y axis
		mouseY = Helper.ClampAngle (mouseY, Y_MinLimit, Y_MaxLimit);

		if (Input.GetAxis ("Mouse ScrollWheel") < -deadZone || 
			Input.GetAxis ("Mouse ScrollWheel") > deadZone) {
			desiredDistance = Mathf.Clamp(Distance - Input.GetAxis ("Mouse ScrollWheel") * MouseWheelSensitivity, DistanceMin, DistanceMax);
		}
	}//HandlePlayerInput()

	void CalculateDesiredPosition()
	{
		// Eval our distance
		Distance = Mathf.SmoothDamp (Distance, desiredDistance, ref velDistance, DistanceSmooth);

		// get desired position
		desiredPositon = CalculatePosition (mouseY, mouseX, Distance);
	}//CalculateDesiredPosition()

	Vector3 CalculatePosition(float rotationX, float rotationY, float distance)
	{
		Vector3 direction = new Vector3 (0, 0, -distance);
		Quaternion rotation = Quaternion.Euler (rotationX, rotationY, 0);

		return TargetLookAt.position + rotation * direction;
	}//CalculatePosition()

	void UpdatePosition()
	{
		// smooth x, y and z 
		var posX = Mathf.SmoothDamp (position.x, desiredPositon.x, ref velX, X_Smooth);
		var posY = Mathf.SmoothDamp (position.y, desiredPositon.y, ref velY, Y_Smooth);
		var posZ = Mathf.SmoothDamp (position.z, desiredPositon.z, ref velZ, X_Smooth);
		position = new Vector3 (posX, posY, posZ);

		// change the position of the camera
		transform.position = position;
		// look at the target
		transform.LookAt (TargetLookAt);
	}//UpdatePosition()

	public void Reset()
	{
		mouseX = 0;
		mouseY = 10f;
		Distance = startDistance;
		desiredDistance = Distance;
	}//Reset()

	public static void UseExistingOrCreateNewMainCamera()
	{
		GameObject tempCamera, targetLookAt;
		TP_Camera myCamera;

		if (Camera.main != null) {
			tempCamera = Camera.main.gameObject;
		} else {
			tempCamera = new GameObject("Main Camera");
			tempCamera.AddComponent<Camera>();
			tempCamera.tag = "MainCamera";
		}

		tempCamera.AddComponent <TP_Camera>();
		myCamera = tempCamera.GetComponent ("TP_Camera") as TP_Camera;

		targetLookAt = GameObject.Find ("targetLookAt") as GameObject;

		if (targetLookAt == null) {
			targetLookAt = new GameObject("targetLookAt");
			targetLookAt.transform.position = Vector3.zero;
		}

		myCamera.TargetLookAt = targetLookAt.transform;
	}//UseExistingOrCreateNewMainCamera()
}